This invention relates to systems and methods for the chemical storage of hydrogen.
Hydrogen has been identified as a major energy resource for the future. The problems and expense associated with hydrogen storage, coupled with the low cost of gasoline, have prevented the use of hydrogen in today's energy market. The technical difficulties, expense and weight of containment vessels are the most significant problems hindering the commercial use of hydrogen energy. Political and environmental concerns, however, are currently stimulating the introduction of energy alternatives in the transportation market. Hydrogen can be a viable alternative if the storage problems are eliminated. Needs exist for a safe, compact relatively lightweight storage system for hydrogen.
One use where hydrogen as an energy source is approaching commercial feasibility is in the area of vehicular transportation. Although hydrogen presently costs about three times as much as gasoline, when environmental and political costs are added to the equation, hydrogen approaches commercial viability. Nationally, our leaders have revived interests in the production of methanol and hydrogen from natural resources. The state of California has enacted legislation which dictates that a set percent of each manufacturer's new car sales must meet Zero Emissions vehicle Standards, starting at two percent in 1998 and rising to ten percent by the year 2003. Other states are likely to enact similar legislation should California's experiment prove successful. Major car manufacturers, including Mercedes Benz, BMW and Mazda are pursuing hydrogen research as a means to comply with future environmental regulations. Needs exist for economically feasible methods and systems for producing and storing hydrogen that are useful in vehicular applications.
The current limiting parameter in creating an acceptable hydrogen-run vehicle is storage. Liquid hydrogen has proven unacceptable due to its cost of production and storage temperature requirements. Compressed gas, while cheaper, requires excessive storage space. Superactivated carbon systems are being developed, but research indicates that constant refrigeration below -120.degree. C. is required. While some progress has been achieved by using metal hydrides to contain hydrogen in automobiles, the resulting storage tank is prohibitively heavy, thereby resulting in reduced driving ranges. Additionally, the hydrides must be heated to temperatures in excess of 300.degree. C. before the bonded hydrogens are released, further limiting the effectiveness of that system. The solid hydrogen storage technique currently generating the most interest is a system that liberates hydrogen from the reaction between powdered iron and water. The oxidation process splits water into hydrogen and oxygen by converting iron to iron oxide. That reaction rate is increased using catalysts. That system has drawbacks, however, including the requirement that the system must be warmed up to several hundred degrees before the self-sustaining hydrogen-producing reaction occurs. That reaction is also irreversible and stoichiometric in iron. Needs exist for hydrogen production and storage systems that are lightweight, low cost and recyclable which do not have prohibitively high or low temperature requirements.
Hydrogen is used in a wide variety of industries including the chemical, electronics, metallurgical, food and aerospace industries. Needs exist in all those industries for hydrogen storage technology that is economically and operationally superior to existing storage methods.